Five common faults of motor soft starter

Equipping the motor with a soft starter is particularly helpful for the smooth starting of the motor and protecting the motor from burning. Here are five common fault problems of soft starters for your reference.

Common faults of motor soft starter

1. The motor cannot start

There are two reasons why the motor cannot start. One is that one of the six thyristors is not triggered reliably or is not conducting. The one-phase circuit passes half-wave DC, and the DC passing through the two-phase winding of the motor has a braking effect on the motor. Not only can the motor not start, but in serious cases, the motor and thyristor will be burned. The second reason is that the motor cannot start due to improper starting parameters or starting curves, which is the most common fault problem.

The former occurs during use, but the probability is lower than the failure rate of the contactor. The latter mostly occurs during the first transportation adjustment and will not occur after adjustment. Most soft starter manufacturers' products will not have this problem, the starting program performance is good, and the factory value setting is highly applicable. Only a few manufacturers' products require the manufacturer to adjust them themselves.

2. SCR burns out

The thyristor is damaged or exploded. This failure has nothing to do with domestic or foreign brands, but its failure rate is lower than that of the contactor. The main problem lies in the installation technology of the pancake-type thyristor.

3. Controller burnout

Compared with soft starters, controllers are the most seriously damaged. Some manufacturers have this kind of failure, and the repair rate exceeds 30%. Imported and joint venture manufacturers rarely have this kind of problem, mainly because the power supply, trigger circuit and input circuit of the controller are easy to burn out.

4. Soft starter malfunction

The motor is in the running state when the soft starter is disturbed and stopped, and the soft starter is disturbed when it is started. The former is common, and the latter has only two brands. The main reasons for the malfunction are product quality problems and circuit layout.

5. The internal plug-in of the soft starter has poor contact

The selection of internal plug-ins for soft starters is not a problem in itself, but it is a problem that domestic manufacturers tend to overlook, which is why failures often occur.